Two curious things...
One - The siding is not correct. It should have been installed level, not on an angle. Weird. Not sure if it will ever be an issue. It likely voids any warranty. Just a guess.
Two - That the basement extends under that stoop. Thats weird too.
I think the coating you want will be fine for aesthetics and to help keep that concrete from eroding away further. Remove any loose material and make sure you prep according to instructions. I do not think the coating would do anything to keep water out of the basement.
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